This invention generally relates to audio identification, and more specifically to generating audio fingerprints based on audio signal complexity.
Real-time identification of audio signals is being increasingly used in various applications. For example, many systems use various audio signal identification schemes to identify the name, artist, and/or album of an unknown song. Currently, various audio signal identification schemes have been developed. In one class of schemes, an audio fingerprint is generated for an audio signal, where the audio fingerprint includes characteristic information about the audio signal usable for identifying the audio signal. The characteristic information about the audio signal may be based on acoustical and perceptual properties of the audio signal. To identify an audio signal, an audio fingerprint generated from the audio signal is compared to a database of reference audio fingerprints.
However, conventional audio identification schemes based on audio fingerprinting have a number of technical problems. For example, current techniques match audio fingerprints from audio signal samples of a specified length. The fingerprint should be long enough to ensure reliable fingerprint identification. Typically different test audio fingerprints have the same lengths regardless of the audio signals to be identified by the audio fingerprints. For example, a conventional technique generates an audio fingerprint from a 5-second sample of an audio signal regardless of the properties of the audio signal. In some instances, the length of the sample may be longer than necessary for an audio signal. For example, an audio signal may be complex and contain many characteristic features, so a 2-second sample may be sufficient to generate an audio fingerprint for reliably identifying the audio signal. However, because the conventional technique uses a 5-second sample for the audio fingerprint, unnecessary delays in identifying the audio signal may occur. In other instances, the length of the sample may be too short to identify an audio signal. For example, a 10-second sample may be needed to generate an audio fingerprint to identify a simple audio signal that does not contain many characteristic features. Hence, the 5-second sample used in the conventional technique may generate an audio fingerprint resulting in an unacceptably large number of false positives.